Juniper SRX 5600 Hardware Manual page 198

SRX 5600 Services Gateway Hardware Guide
DC Power Electrical Safety Guidelines and Warnings
When working with DC-powered equipment, observe the following guidelines and
warnings:
DC Power Electrical Safety Guidelines
The following electrical safety guidelines apply to a DC-powered services gateway:
NOTE: Primary overcurrent protection is provided by the building circuit breaker.
This breaker should protect against excess currents, short circuits, and earth faults
in accordance with NEC ANSI/NFPA70.
172
Safety Guidelines and Warnings
Blue—Neutral
Brown—Live
DC Power Electrical Safety Guidelines on page 172
Copper Conductors Warning on page 173
DC Power Disconnection Warning on page 173
DC Power Grounding Requirements and Warning on page 174
DC Power Wiring Sequence Warning on page 175
DC Power Wiring Terminations Warning on page 177
A DC-powered services gateway is equipped with a DC terminal block that is
rated for the power requirements of a maximally configured services gateway.
To supply sufficient power, terminate the DC input wiring on a facility DC source
capable of supplying at least 58 A (32 A per feed) @ –48 VDC for the system.
We recommend that the 48 VDC facility DC source be equipped with a circuit
breaker rated at 125% of the power provisioned for the input minimum, or as
required by local code. Incorporate an easily accessible disconnect device into
the facility wiring. In the United States and Canada, the –48 VDC facility should
be equipped with a circuit breaker rated a minimum of 125% of the power
provisioned for the input in accordance with the National Electrical Code in the
US and the Canadian Electrical Code in Canada. Be sure to connect the ground
wire or conduit to a solid office (earth) ground. A closed loop ring is recommended
for terminating the ground conductor at the ground stud.
Run two wires from the circuit breaker box to a source of 48 VDC. Use appropriate
gauge wire to handle up to 50 A.
A DC-powered services gateway that is equipped with a DC terminal block is
intended only for installation in a restricted access location. In the United States,
a restricted access area is one in accordance with Articles 110-16, 110-17, and
110-18 of the National Electrical Code ANSI/NFPA 70.
Ensure that the polarity of the DC input wiring is correct. Under certain conditions,
connections with reversed polarity might trip the primary circuit breaker or
damage the equipment.